CVE-2021-34557

4.6 MEDIUM 0.5% exploit odds Fix listed

What it is

XScreenSaver 5.45 can be bypassed if the machine has more than ten disconnectable video outputs. A buffer overflow in update_screen_layout() allows an attacker to bypass the standard screen lock authentication mechanism by crashing XScreenSaver. The attacker must physically disconnect many video outputs.

At a glance

Exploitability: Can be exploited with physical access without logging in. High risk of service disruption.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-06-10 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:56 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 4.6 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-06-10 16:15 UTC
Last modified: 2026-06-17 03:56 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-120 · Classic buffer overflow
Record status: Modified

Affected

Xscreensaver Project Xscreensaver 5.45
Fedoraproject Fedora 33

Attack profile CVSS 3.1 · 4.6

Attack vector: Physical
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-34557.md and follow it. Check whether this project is affected by CVE-2021-34557. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record